1. Field of the Invention
The field of the invention is data processing, or, more specifically, methods, systems, and products for failback to a primary communications adapter.
2. Description of Related Art
EtherChannel is a link aggregation technology that allows several Ethernet adapters to be aggregated together to form a single pseudo-Ethernet adapter having increased bandwidth and fault-tolerance. All the aggregated adapters in the EtherChannel are typically given the same link layer address and are treated by remote systems as a single adapter. One benefit of EtherChannel is that the aggregated adapters have the network bandwidth of all of their adapters in a single network presence. If a single adapter fails, network traffic is automatically sent on the next available adapter in the EtherChannel without disruption to existing user connections.
Although failure of the EtherChannel is less likely than the failure of a single Ethernet adapter, failure of the EtherChannel does occur. To provide failover protection for the EtherChannel, typically a backup Ethernet adapter remains idle until all the primary adapters in the EtherChannel fail. When the primary adapters in the EtherChannel fail, the backup adapter is activated and administers all Ethernet traffic until at least one of the primary adapters recovers. When at least one of the primary adapters recovers, the primary channel is again available for all traffic and the backup adapter is reset to its idle state.
It is desirable to return Ethernet traffic across the primary EtherChannel as soon as the primary EtherChannel recovers, because the EtherChannel has more bandwidth than the backup adapter. Conventional EtherChannel drivers provide automatic failover to a backup adapter and dynamic reconfiguration of the primary EtherChannel. Dynamic reconfiguration of the primary EthernetChannel typically includes re-establishing electrical connectivity in the physical layer Ethernet adapter and initializing the ports connecting LAN segments in the link layer. When electrical connectivity to the adapter is established the adapter sends a ‘link up event’ to the EtherChannel driver. Although there is electrical connectivity to the physical layer Ethernet adapter, the Ethernet adapter is not capable of sending packets until dynamic reconfiguration process initializes the ports connecting segments in the LAN, thereby allowing packets received through the adapter to be forwarded in the LAN. Failback to the primary EtherChannel before the primary adapters are capable of sending packets results in lost packet traffic. There is therefore a need for improved failback to a primary communications adapter.